We plan to study: (1) The regulatory properties and chemical characteristics of liver phosphorylase. (2) The role of the subunits of muscle phosphorylase kinase in catalysis and regulation. (3) The specificity requirements of phosphorylase kinase and cAMP-dependent protein kinase on synthetic peptides. (4) The structural features of the N-terminal cyanogen bromide fragment of phosphorylase-phosphorylation and dephosphorylation effects. (5) The role of pyridoxal phosphate in phosphorylase and chemical features of arginyl residues in the binding site. These studies on purified enzymes are focused to give a better understanding of structure-function relationships of enzymes involved in the regulation of glycogen metabolism.